It has been argued that quasi-compulsory treatment (QCT) may be considered ethical (under some specific conditions) for drug dependent offenders who have committed criminal offences for whom the usual penal sanction would be more restrictive of liberty than the forms of treatment that they are offered as a constrained, quasi-compulsory choice. It has briefly reviewed research that suggests that QCT may be as effective as treatment that is entered into voluntarily. This may help individuals to reduce their drug use and offending and to improve their health, but it is unlikely to have large effects on population levels of drug use and crime.